Changes in the oculas surface after hypotensive surgery

BACKGROUND: Hundreds of studies are dedicated to the negative effects of glaucoma therapy on the ocular surface. At the same time, the state of the eye surface after successful hypotensive surgery, which resulted in the cessation or significant reduction of medical therapy, has not been studied.

AIM: To identify ocular surface changes after glaucoma surgery.

MATERIALS AND METHODS: The study group consisted of 475 consecutively enrolled patients who were operated during 2016–2020 in Saint Petersburg Multidisciplinary City Hospital No. 2 for primary open-angle unstable glaucoma, and then observed for 6 to 24 months. Trabeculectomy (TE) was used as the first hypotensive procedure (418 patients), as re-operation — TE (25 patients) or Ahmed valve implantation (32 patients) were chosen. Using statistical methods, the dynamics of symptoms (OSDI) and signs [tear film break-up time (TBUT) and reflex tear production defined by Schirmer I test] depending on outcome (“complete” or “partial” success and “total failure”) were analyzed.

RESULTS: The cessation of the pharmacological load due to the “complete success” of the surgery was accompanied by pronounced (two-fold) and long (for at least two years) decrease of OSDI scores. The obliged, even partial, return to instillations by patients, who were included into the subgroup of “partial success”, within six months, transformed the achieved differences into insignificant ones. TBUT at “complete” and “partial success” significantly increased at all end-points of the study, significantly differing from the similar indicator in the subgroup “total failure”. The results of the Schirmer I test against the background of “complete success” of the operation showed a statistically significant increase, compared to the baseline , delayed for six months, throughout the whole further follow-up period. Patients entering the “partial success” subgroup in 24 months after surgery, also showed a significant increase in tear secretion. The failure of glaucoma surgery was accompanied by a brief and insignificant improvement in all scores.

CONCLUSIONS: The hypotensive surgery, which lead to “complete success”, was accompanied by a significant improvement of the ocular surface state. Restart of local therapy reduces achieved results. Failure of surgical treatment is associated with minimal fluctuations of the studied parameters.